Feeding strategy aims to boost broiler leg strength

Animal welfare is a complex concept but there is general agreement within the scientific community and beyond that farm animals should be able to move easily and be in good health.

One welfare issue of particular interest in the poultry sector is lameness in broiler chickens. According to a group of French researchers, producers often underestimate the amount of lameness in their broiler flocks and in doing so they risk reducing the birds’ welfare as well as product quality and profitability.

Between 10 and 30% of birds in European broiler flocks have abnormal gait and some leg disorders caused by bone and joint infections as well as skeletal abnormalities may be painful. The former are a result of a fast growth rate during the first few weeks of life. Fast growth placed abnormally high loads on relatively immature bones and joints, causing skeletal abnormalities.

One possible solution is to design a feed strategy that can reduce growth at this early stage, so significantly reduce lameness and, thereby, improve animal welfare. “But our key challenge was to reduce growth without adversely affecting flock performance,” says Christine Leterrier of the French National Institute For Agricultural Research (INRA).

So she led a project with the aim of developing a successful diet regime to reduce lameness based on slowing down the speed at which birds grow during their first few weeks and then speeding it up once their bones have developed. “By using a new combination of two diets and a sequential feeding method, we discovered that this can be achieved without any reduction in final carcass weight,” she says.

So what does the feeding strategy involve? They recommend a 48-hour feeding cycle with two diets instead of the traditional continuous distribution of a single diet.

For the first seven days of life, broiler chicks should be fed a standard starter diet. Then, from day eight to day 28 the diets should rotate every 24 hours between a low energy, high protein (E-P+) diet and a high energy, low protein (E+P-) diet.

That makes for a total of 10 cycles of E-P+, E+P-. Following this, birds should then be given a standard finishing diet from day 29 onwards.

“In total, this novel regime not only reduced instances of lameness, but also brought the broilers up to standard slaughter weight without the need any additional feeding days.”

For this to work, the E-P+ diet should contain about 97% of the energy and 121% of the protein of a standard diet while the E+P- diet should be 103% of the energy of a standard one with 79% of the protein.

To conclude, we believe the sequential feeding method could prove to be a win-win situation for both birds and producers. It could improve the birds’ welfare by reducing lameness at no extra cost while safeguarding the producers’ profits at the same time.

However, the researchers added that the low energy diet should be given first in order to avoid any reduction in body weight at slaughter.

Another advantage was that the cost of the sequential diet may be lower than a standard diet, as it can contain more cost effective protein-rich feeds such as rapeseed and Dried Distillers Grains with Solubles (DDGS) – a byproduct from bioethanol production. This is cause rapeseed meal and DDGS can effectively replace other more expensive protein rich feeds in the E-P+ part of the cycle.

Project at a glance

The Problem: Between 10 and 30% of birds in European flocks have abnormal gait and some may suffer from leg disorders and most of these are the result of a fast growth rate during the bird’s first few weeks of life. To address this, French researchers designed a new strategy aimed at reducing growth without compromising carcass yield.

This reduction in lameness was achieved without compromising carcass weight

This approach could also reduce feed cost by allowing the use of biofuel byproducts

Welfare Quality

Welfare Quality is a European research project focusing on the integration of animal welfare in the food quality chain. The project aims to accommodate consumer concerns and market demands, develop reliable on-farm monitoring systems, product information systems, and practical species-specific strategies to improve farm animal welfare. Starting in 2004, the five year project involves 44 institutes and universities from Europe and Latin America.